{ pkgs, ... }:
let mainProgram = "proton-mail";
    srcHashes = {
      universal-darwin = "sha256-JfZwHFp0aZtHcbP7tyG7uqFs2w+LWKfnfyuxxpxDJZ8=";
      x86_64-linux = "sha256-En5vkTHYtwN6GMgbtyhzsPqknOPRO9KlTqZfbBFaIFQ=";
    };
in
pkgs.stdenv.mkDerivation rec {
  pname = mainProgram;
  version = "1.0.5";
  nativeBuildInputs = [
    pkgs.makeWrapper
  ] 
  ++ pkgs.lib.optional pkgs.stdenv.isLinux pkgs.dpkg 
  ++ pkgs.lib.optional pkgs.stdenv.isDarwin pkgs.unzip;
  src = pkgs.fetchurl {
    url =
      if pkgs.stdenv.isDarwin then
        "https://github.com/ProtonMail/inbox-desktop/releases/download/${version}/Proton.Mail-darwin-universal-${version}.zip"
      else
        "https://github.com/ProtonMail/inbox-desktop/releases/download/${version}/proton-mail_${version}_amd64.deb";
    sha256 =
      {
        x86_64-linux = srcHashes.x86_64-linux;
        x86_64-darwin = srcHashes.universal-darwin;
        aarch64-darwin = srcHashes.universal-darwin;
      }
      .${pkgs.stdenv.hostPlatform.system} or (throw "unsupported system ${pkgs.stdenv.hostPlatform.system}");
  };

  sourceRoot = pkgs.lib.optionalString pkgs.stdenv.isDarwin ".";

  dontConfigure = true;
  dontBuild = true;

  installPhase =
    let
      darwin = ''
        mkdir -p $out/{Applications,bin}
        cp -r "Proton Mail.app" $out/Applications/
        makeWrapper $out/Applications/"Proton Mail.app"/Contents/MacOS/Proton\ Mail $out/bin/protonmail-desktop
      '';
      linux = ''
        runHook preInstall
        mkdir -p $out
        cp -r usr/share/ $out/
        cp -r usr/lib/ $out/
      '';

    in
    ''
      runHook preInstall

      ${if pkgs.stdenv.isDarwin then darwin else linux}

      runHook postInstall
    '';

    preFixup = pkgs.lib.optionalString pkgs.stdenv.isLinux ''
      makeWrapper ${pkgs.steam-run}/bin/steam-run $out/bin/${mainProgram} \
        --add-flags "$out'/lib/proton-mail/Proton Mail Beta'"
    '';
}